VIDEO: Relief for residents as river peaks lower than expected

A tense night for residents in the northern NSW town of Maclean has ended in relief after the swollen Clarence River peaked below the expected level.

The State Emergency Service said there were no reports of inundated properties at 6.30am and the river was holding steady at 3.08 metres, below the predicted 3.2-metre peak.

However authorities were closely monitoring conditions as the levee wall in Maclean is 3.3 metres.

More than 750 residents in low-lying parts of the town were ordered to evacuate just after 5.30pm on Tuesday based on the Bureau of Meteorology's predicted flood peak, which was expected at 6am.

NSW SES spokeswoman Becky Gollings said the evacuation order remained in place on Wednesday morning.

"We're pretty confident that we won't get any inundation but, because the peak prediction is just under the crest of the levee, we've still got that evacuation order in place. It's just too fine to call it. We're always going to put people's safety first," she said.

"Once that peak reaches and it starts to subside we will get our crews in there to assess the area and if it's all deemed safe then we will issue the all clear."

About 190 people on Harwood Island, downstream of Maclean, were also ordered to evacuate at 7.15pm on Tuesday, but properties in that area also appeared to have escaped flooding.

Harwood Island and Maclean, which is about 45 kilometres downstream of Grafton, were the last towns where authorities feared there would be major flooding before the Clarence River flows out to sea.

In Grafton, where the river peaked just two centimetres below the city's levee wall on Tuesday, residents were allowed back into their homes about 9.30pm as the river continued to recede.

Flood levels there were the biggest in the city's history.

"This is a sight that has never been seen by white man," said the mayor of Clarence Valley, Richie Williamson.

"The Clarence has never been recorded above 7.9 metres. It's an awesome spectacle."

Bushgrove. Photo: Barry O'Farrell via Twitter

Photo: FRANK REDWARD

Ulnarra where the levies have seen water over the top. Photo: Barry O'Farrell via Twitter